Bit-rate guided frequency weighting matrix selection

Abstract

A system and method for generating a frequency weighted (FW) matrix for use in a Fine-Granularity-Scalability (FGS) video coding system. The system comprises: a system for plotting the average discrete cosine transform (DCT) residuals versus the zigzag DCT scan line locations for a sample video frame encoded both at a predetermined base layer bit-rate and at approximately three times the predetermined base layer bit-rate; a system for generating the difference plot of DCT residuals versus the zigzag DCT scan line locations for the video frame encoded at both the predetermined base layer bit-rate and at approximately three times the predetermined base layer bit-rate; and a system for matching and normalizing a staircase curve to the average difference plot, wherein the staircase curve values can be further mapped into the weights for the FW matrix.

Description

BACKGROUND OF THE INVENTION[0001]1. Technical Field[0002]The present invention relates generally to scaling of encoded video, and more particularly relates to a system and method for selecting a frequency weighting (FW) matrix for a system implementing Fine-Granularity-Scalability (FGS) technology.[0003]2. Related Art[0004]The Fine-Granularity-Scalability (FGS) coding profile was adopted as part of the MPEG-4 standard in March 2001. The MPEG-4 FGS profile encodes a video sequence into two bit streams with different transmission priorities that can accommodate a large range of bit-rates: the base layer (BL) video stream and the enhancement layer (EL) video stream. The BL is coded using the MPEG-4 non-scalable coding scheme that employs motion-compensation and block-based DCT (discrete cosine transform) coding. The BL is coded to an acceptable minimal bit-rate (the base-layer bit-rate), such that the available bandwidth over the time-varying network is higher than the base-layer bit-r...

AI Technical Summary

Benefits of technology

[0009]The present invention addresses the above-mentioned problem, as well as others, by providing a novel FW matrix selection method using BL DCT residual difference at critical quality bit-rates. In a first aspect, the invention provides a system for generating a frequency weighting (FW) matrix for use in a Fine-Granularity-Scalability (FGS) video coding system, comprising: a system for generating average discrete cosine transform (DCT) residuals for a sample video frame encoded both at a predetermined base layer bit-rate and at approximately three times the predetermined base layer bit-rate; a system for plotting a difference curve of the generated average DCT residuals, wherein the difference curve is plotted by DCT coefficient locations corresponding to a DCT zigzag scan line; and a system for matching a staircase curve to the difference curve.

Problems solved by technology

For most video sequences, the lower accuracy of the DC and first AC's EL residuals translates in a reduced visual quality at the decoder side.

However, the generic energy dissipation guideline cannot provide hints for determining the exact quantitative values of the FW matrix.

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